Bellow Sealed valves are available in two bonnet designs. The first design is the Bolted Bonnet, with male-female joint, spiral wound gasket, made in F304L/graphite.
Ring joint gasket are also available on request. The second design is the welded bonnet. with a threaded and seal welded joint. On request a full penetration strength welded joint is available.

Construction is as follows
  Full port or conventional port;
  Outsied screw and yoke (OS&Y);
  Self-centering gland and plate;
  Bolted bonnet with spiral-wound gasket or threaded and seal welded bonnet;
  Integral backseat;
  Socket welded end to ASME B16.11;
  Screwed ends(NPT) to ANSI/ASME B1.20.1.